Small-screen computing devices continue to proliferate, such as smartphones and computing bracelets, rings, and watches. Like many computing devices, these small-screen devices often use virtual keyboards to interact with users. On these small screens, however, many people find interacting through virtual keyboards to be difficult, as they often result in slow and inaccurate inputs. This frustrates users and limits the applicability of small-screen computing devices. This problem has been addressed in part through screen-based gesture recognition techniques. These screen-based gestures, however, still struggle from substantial usability issues due to the size of these screens.
To address this problem, optical finger- and hand-tracking techniques have been developed, which enable gesture tracking not made on the screen. These optical techniques, however, have been large, costly, or inaccurate thereby limiting their usefulness in addressing usability issues with small-screen computing devices.
Furthermore, control through gestures continues to proliferate for other devices and uses, such as from mid to great distances. People not only wish to control devices near to them, but also those from medium to large distances, such as to control a stereo across a room, a thermostat in a different room, or a television that is a few meters away.